Internet-based search engines traditionally employ common image search techniques for locating digital image content on the World Wide Web. These well-known image search techniques can be categorized into “text-based” image searches and “visually-based” image searches.
Traditional text-based image searches may receive a text-based query used for searching a database having keyword-tagged images to generate a resulting set of images that each has one or more keyword tags matching the text-based query. These text-based searches rely primarily on the quality of the keyword tags associated with an image, while ignoring the image's visual information. Traditional visually-based image searches, on the other hand, may receive an image as a visually-based query for searching a database of images, irrespective of the each image having keyword tags associated therewith, to generate a resulting set of images that each has visually similar characteristics to the visually-based query image.
While traditional image search techniques can oftentimes generate desirable results, the generation of quality results in text-based image searches may depend on the quality of the images in the image database on which the search is conducted. With particular regards to visually-based image searches, the generation of quality results may depend on the quality, or even the existence of, the visually-based search query itself. For example, a text-based image search can only produce desirable results if the database on which the search is performed includes keyword-tagged images. In this regard, if an image database comprised, among many other images, thousands of images of a football game, none of which had a keyword tag associated with keywords “football” or “game,” a text-based image search with a text-based query (i.e., a descriptive keyword) of “football game” would not generate any desirable results. In another example, a visually-based image search can only generate desirable results if provided with a visually-based query (i.e., an exemplary image). In this regard, if a user wanted to search the image database to locate images from the football game, the user would need to have at least one image having visually similar characteristics to the images from the football game to construct the search query. As such, traditional image search techniques can be rather restrictive and limited in scope.